scholarly journals Photocatalytic Activity and Optical Properties of Blue Persistent Phosphors under UV and Solar Irradiation

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
C. R. García ◽  
L. A. Diaz-Torres ◽  
J. Oliva ◽  
M. T. Romero ◽  
P. Salas
Keyword(s):  
Photocatalytic Activity ◽  
Annealing Temperature ◽  
Uv Light ◽  
Solar Irradiation ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Water Cleaning ◽  
Different Temperatures ◽  
The Eu

Blue phosphorescent strontium aluminosilicate powders were prepared by combustion synthesis route and a postannealing treatments at different temperatures. X-ray diffraction analysis showed that phosphors are composed of two main hexagonal phases: SrAl2O4and Sr3Al32O51. The morphology of the phosphors changed from micrograins (1000°C) to a mixture of bars and hexagons (1200°C) and finally to only hexagons (1300°C) as the annealing temperature is increased. Photoluminescence spectra showed a strong blue-green phosphorescent emission centered atλem=455 nm, which is associated with4f65d1→4f6  (8S7/2)transition of the Eu2+. The sample annealed at 1200°C presents the highest luminance value (40 Cd/m2) with CIE coordinates (0.1589, 0.1972). Also, the photocatalytic degradation of methylene blue (MB) under UV light (at 365 nm) was monitored. Samples annealed at 1000°C and 1300°C presented the highest percentage of degradation (32% and 38.5%, resp.) after 360 min. In the case of photocatalytic activity under solar irradiation, the samples annealed at 1000°C, 1150°C, and 1200°C produced total degradation of MB after only 300 min. Hence, the results obtained with solar photocatalysis suggest that our powders could be useful for water cleaning in water treatment plants.

Photocatalytic Activity of Fe-Doped ZnO/Montmorillonite Nanocomposite for Degradation of Malachite Green

2015 ◽  
Vol 827 ◽  
pp. 19-24 ◽  
Author(s):  
Nur Afifah ◽  
Nadia Febiana Djaja ◽  
Rosari Saleh
Keyword(s):  
Photocatalytic Activity ◽  
Malachite Green ◽  
Organic Dyes ◽  
Uv Light ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spin Resonance ◽  
Doped Zno ◽  
Co Precipitation

In this study, the photocatalytic activity of pure Fe- doped ZnO and Fe- doped ZnO/Montmorillonite nanocomposite has been investigated for the degradation of malachite green under UV light irradiation. Both photocatalysts were synthesized using co-precipitation method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier-transform infrared absorption, and electron spin resonance. The results showed that the photocatalytic efficiency is better in the presence of montmorillonite compared to pure Fe- doped ZnO. To detect the possible reactive species involved in degradation of organic dyes control experiments with introducing scavengers into the solution of organic dyes were carried out. It is found that electron plays an important role in the degradation of malachite green.

Fabrication and Luminescence Properties of Y2O3:Eu3+/AAO Composite

2012 ◽  
Vol 583 ◽  
pp. 199-202
Author(s):  
Su Wen Li ◽  
Shu Guang Ju
Keyword(s):  
Anodic Aluminum Oxide ◽  
Annealing Temperature ◽  
Anodic Aluminum Oxide Template ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anodic Aluminum ◽  
Local Environments ◽  
Spectral Components ◽  
The Eu

Uniform Eu3+ doped Y2O3 nanowires with diameters of 50 nm in the anodic aluminum oxide template (AAO) have been fabricated. The Y2O3:Eu3+/AAO composite nanowires were characterized by using powder X-ray diffraction (XRD), scanning electron microscope (SEM) and spectrofluorometer techniques. The results indicate that with the increasing annealing temperature and time the excitation band of Eu3+ in Y2O3: Eu3+/AAO composite blue shifted, the intensity ratio of 5D0-7F2 to 5D0-7F1 decreased and the lifetime of the Eu3+ ions in composite became longer. In the composite annealed at 1000 °C, two spectral components were detected, corresponding to two different local environments, i.e. the Eu3+ ions in cubic phase and in amorphous phase, respectively.

Hydrothermal Synthesis and Photocatalytic Properties of Flower-Like CdS Nanostructures

2011 ◽  
Vol 335-336 ◽  
pp. 460-463 ◽  
Author(s):  
Hong Mei Wang ◽  
Da Peng Zhou ◽  
Yuan Lian ◽  
Ming Pang ◽  
Dan Liu
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Sulfur Source ◽  
X Ray Diffraction ◽  
Facile Hydrothermal Method ◽  
X Ray ◽  
Transmission Electron ◽  
Cds Nanostructures

Hexagonal flower-like CdS nanostructures were successfully synthesized through a facile hydrothermal method with thiourea as sulfur source. By combining the results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), the structural and morphological characterizations of the products were performed. The photocatalytic activity of CdS nanostructures had been tested by degradation of Rhodamine B (RB) under UV light compared to commercial CdS powders, which indicated that the as-syntherized CdS nanostructures exhibited enhanced photocatalytic activity for degradation of RB. The possible growth mechanism of CdS nanostructures was proposed in the end.

scholarly journals Synthesis and Catalase Mimic Activity of MnO2 Nano Powder Prepared by Hydrothermal Process

2019 ◽  
Vol 27 (2) ◽  
pp. 228-237 ◽  
Author(s):  
Rashed T. Rasheed ◽  
Sariya D. Al-Algawi ◽  
Rosul M. N.
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Annealing Temperature ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Powder ◽  
Atomic Force ◽  
Different Temperatures ◽  
Scanning Electron

Manganese dioxide (MnO2) nanopowder has been synthesized by hydrothermal method. MnO2 was annealed at different temperatures (250, 400, 550, 700˚C). The crystal structure and surface morphology of these nanostructures were characterized by X-ray diffraction (XRD), Atomic Force Microscope (AFM) and Scanning Electron Microscopy (SEM). The catalase mimic activity (catalytic activity) of MnO2 against hydrogen peroxide (H2O2) was studied by using the new method and found that 400˚C is the best annealing temperature.

scholarly journals Preparation and Photocatalytic Activity of TiO2/Fine Char for Removal of Rhodamine B

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Mingjie Ma ◽  
Weijie Guo ◽  
Zhengpeng Yang ◽  
Shanxiu Huang ◽  
Guanyu Wang
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Rhodamine B ◽  
Uv Light ◽  
Sol Gel ◽  
Tetrabutyl Titanate ◽  
Light Illumination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Light Irradiation

TiO2/fine char (FC) photocatalyst was prepared via sol-gel method with tetrabutyl titanate as the precursor and FC as the carrier. The structural property of TiO2/FC photocatalyst was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the photocatalytic activity of TiO2/FC was evaluated by photocatalytic degradation of rhodamine B (RhB) aqueous solution under UV light irradiation. The results showed that TiO2was successfully coated on the surface of FC, and the TiO2/FC photocatalyst had better photocatalytic efficiency and stability for degradation of RhB under UV light illumination as compared to that of the pure TiO2and FC. The study provided a novel way for the application of FC to the photocatalytic degradation of organic wastes.

OPTICAL AND STRUCTURAL PROPERTIES OF Ag NANOPARTICLES Eu OXIDE FILMS

2008 ◽  
Vol 07 (06) ◽  
pp. 339-344 ◽  
Author(s):  
A. A. DAKHEL
Keyword(s):  
Lattice Parameter ◽  
Europium Oxide ◽  
Silicon Substrates ◽  
Ag Nanoparticle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanoparticle Radius ◽  
Different Temperatures ◽  
Bcc Structure ◽  
The Eu

Silver-incorporated europium oxide thin films have been prepared by the successive evaporation method on quartz and silicon substrates. The silver concentration was 2.5% and 8.9% respectively, as measured by X-ray fluorescence. X-ray diffraction revealed that the Eu oxide of these samples remained amorphous after preannealing at 450°C; however, it crystallized in bcc structure at 800°C. The lattice parameter of the crystallized Eu oxide was larger than that of the bulk, due to the adsorption of Ag + ions, which have a higher ionic radius. The optical absorption of the samples manifested the surface plasmon resonance (SPR) phenomenon, which varied with the Ag content and preannealings of the samples at different temperatures. The Ag nanoparticle radius was estimated with the Mie classical theory by using the SPR data analysis.

Effect of Fe Incorporation on the Photocatalytic Activity of TiO2 by Sol-Gel Method

2015 ◽  
Vol 1087 ◽  
pp. 218-222
Author(s):  
Siti Aida Ibrahim ◽  
Srimala Sreekantan
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Sol Gel ◽  
Combination Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Light Irradiation ◽  
Vis Spectroscopy ◽  
Visible Irradiation ◽  
Emission Microscopy

Nanostructured Fe-TiO2 and TiO2 with anatase structure were synthesized via combination method of sol-gel and peptization process. The samples were characterized by X-ray diffraction (XRD), Transmission emission microscopy (TEM) and UV-Vis spectroscopy (UV-Vis). The presence of Fe3+ ion shifted the absorption profile of TiO2 to the longer wavelength side of the spectrum, indicating an obvious photocatalytic activity under visible irradiation. Photocatalytic activity of the samples were evaluated by methyl orange (MO) discolouration under UV-light irradiation. Compared with the pure TiO2 nanoparticles, the Fe-TiO2 nanoparticles exhibited higher photocatalytic activity with 95% discoloration within 2 h.

Electrical Properties of a High-Tc Superconductor-Polymer Compersite

2007 ◽  
Vol 546-549 ◽  
pp. 1989-1992
Author(s):  
Fang Gao Chang ◽  
Kun Fang ◽  
Gui Lin Song
Keyword(s):  
Annealing Temperature ◽  
Solid State Reaction Method ◽  
Gravimetric Analysis ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Different Temperatures ◽  
Zero Resistance ◽  
Composite Samples

A superconductor-polymer composite of Bi1.8Pb0.4Sr2Ca2Cu3Oy and ethylene propylene rubber (EPR) was prepared by conventional solid-state reaction method. The phase structure of the composite was characterized by using x-ray diffraction technique. The resistivity of composite samples annealed at different temperatures was measured between 40K and 300K. The results indicate that the resistivity of the as-prepared composite increases with increasing EPR content and shows essentially a semiconducting behavior above Tc. For fixed EPR content, the resistivity of composite samples decreases with increasing annealing temperature. The composite begins to show some signs of superconducting transition at an annealing temperature of 700 °C and zero resistance is reached for samples sintered at 800°C. Thermal gravimetric analysis (TGA) on the composite confirmed that 65% of the EPR content still present in the superconducting composite samples. SEM was used to investigate the surface morphology of the composites. Preliminary results show that the mechanical properties of the composite have been much improved compared with its parent superconductor ceramics.

scholarly journals Effects of mechanical activation on structure and photocatalytic properties of ZnO powders

2013 ◽  
Vol 11 (11) ◽  
pp. 1780-1785 ◽  
Author(s):  
Maria Gancheva ◽  
Reni Iordanova ◽  
Yanko Dimitriev ◽  
Georgi Avdeev ◽  
Tzvetoslav Iliev
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Reflectance Spectroscopy ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Time Intervals ◽  
X Ray ◽  
Uv Light Irradiation ◽  
Band Position ◽  
Zno Powders

AbstractZinc oxide (ZnO) was mechanically activated in air using a planetary ball mill using varying milling speeds and time. The obtained samples were analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and UV-Vis diffusion reflectance spectroscopy. The photocatalytic activity of the mechanically treated ZnO powders were investigated in the reaction of Malachite Green (MG) degradation in aqueous solution under UV-light irradiation. A decrease in the crystallite size (from 90 to 10 nm) accompanied by an increase of microstrains and lattice parameters were established applying different milling speeds. The agglomeration of the particles was observed by SEM analysis. The absorption spectra of the initial and mechanically activated ZnO samples show shifting of the band position from 360 to 330 nm, which can be related to decrease in the crystalline size. The ZnO powders activated at lower milling speeds (for shorter time intervals) exhibit highest photocatalytic activity.

Effects of Nd Doping on the Photocatalytic Behavior of Cu11O2 (VO4)6

2011 ◽  
Vol 393-395 ◽  
pp. 1181-1184
Author(s):  
Min Wang ◽  
Qiong Liu ◽  
Qi Xing
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Photodegradation Rate ◽  
Triclinic Phase ◽  
Degradation Of Methyl Orange ◽  
Scanning Electron

Nd-doped Cu11O2 (VO4)6 photocatalyst was synthesized by complexing Sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy Dispersive X-Ray Spectroscopy(EDX). The photocatalytic activity of Nd-doped Cu11O2 (VO4)6 was evaluated by photocatalytic degradation of methyl orange (MO) solution under UV-light. It revealed that the Nd-doped Cu11O2 (VO4)6 prepared with the molar ratio of citric acid to metal inons be 2:1, Nd/Cu molar ratio of 2%, pH=7 and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 95.73% or so in 60min under 20W ultraviolet lamp.

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